I want to understand how nervous systems are organized. To this end, I have studied the synaptic and cellular organization of the stomatogastric ganglion to see how it generates particular motor patterns. This project includes four independent tests of a hypothesis about the mechanism generating one motor pattern -- the gastric rhythm. These tests are: 1. Reversible interference with synaptic transmission. 2. Controlled interference with spontaneous activity in particular neurons. 3. Anatomical investigation of the organization of the ganglion. 4. Analytical modelling of the synaptic network. It is also necessary to verify and quantify known and suspected interactions between some neurons, and to measure dynamic characteristics of particular neurons and synapses. These experiments are worthwhile since if they verify the hypothesis, and if we can usefully model the organization of the ganglion, then we will have a complete description in terms of its neuronal and synaptic properties, and an explanation of how it generates the motor patterns. BIBLIOGRAPHIC REFERENCE: Mulloney, B. & A.I. Selverston (1977). J. Comp. Physiol. (in press). Organization of the Stomatogastric Ganglion of the Spiny Lobster V. Coordination of the Gastric and Pyloric Systems.